The present invention relates to apparatus for artificially inducing sleep in a patient.
In recent years, insomnia has become the subject of medical and psychological treatment and study with the direction being to devise a system which will conveniently and efficiently induce sleep. Electric impulse devices have gained in favor since chemotherapy treatments often involve substances that act upon the central nervous system and there is a growing aversion to the utilization of chemicals to cure what may otherwise be treated.
Electrosleep is elicited by a train of electrical pulses in the form of a waveshape such as sinusoidal, square, triangular and spike. The spike form is presently gaining favor and is generally of 1 to 2 milliseconds duration at about 20 volts amplitude and 100 microamperes current. Other waveshapes have the disadvantage of causing pain at the electrodes for the equivalent amplitude of the spike. The repetition frequency employed for all waveshapes is generally between 5 and 200 cycles depending somewhat on the subjective choice of the patient. The amplitude of the waveshape is also subjective to the desire or fancy of the patient and for this purpose it is desirable for the equipment to be conveniently adjustable. During treatment, the patient feels nothing and is unaware of the electrical stimulation. For waveshapes other than the spike, with pulse durations of greater than 2 milliseconds the patient may be aware of a visual sensation caused by the electrical stimulation of the retina of the eye, and this stimulation appears to effect the ganglia in the retina of the eye. Use of different waveshapes have been the result of investigation for the optimized waveshape and the instant invention presents what thus far is believed to be a highly effective waveform.
Electrodes have been standardized to placement, polarity and use of some contact enhancing substance. Placement of the electrodes is generally one electrode over each eye lid and one electrode over each mastoid. The polarity of the electrodes in the front or eye lid electrodes is negative and the back or mastoidal electrodes positive. The contact enhancing substances in use are conductive jellies developed for use in electroencephalography and electrocardiography, as well as physiological saline solution.
Electrosleep has proven to be a useful technique to elicit relaxation or sleep in a large number of people. The disadvantages of previous techniques are the time consumed by the treatment and temporary visual disturbances following the treatment. Time problems have limited its use clinically where clinicians must set up the apparatus, adjust it to the individual patient, monitor the treatment, and provide for bedspace for the treatment. The distortion of vision following the treatment is caused by the eye lid electrodes exerting pressure on the eyeball causing blurred vision for up to 30 minutes after the treatment. The instant invention is designed to overcome most of the handicaps of the prior art apparatus. Specifically it is directed toward rendering a useful apparatus portable and easy to apply, and also it is designed so that the least possible visual disturbances are afflicted on the patient by reducing the amount of time necessary to employ the treatment.
Among the prior art is the Hoody et al U.S. Pat. No. 3,160,159, Dec. 8, 1964. This patent describes the use of a multivibrator which produces a spike waveform that is designed to generate reticular formation stimulus signals. This patent also generally refers to the desirability to render an acceptable unit portable for use on the patient in the home or other areas outside of the hospital.
The prior art is deficient in providing a portable device which will both generate reticular formation stimulus signals as well as visual stimulus signals. A small, compact and conveniently worn device, that may be employed outside of the hospital or the physicians office has been required by the practitioners for some time.